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PhysicsMediumMCQ2004 · Unknown

Q70.The work function of a substance is 4.0eV . Then longest wavelength of light that can cause photoelectron emission from this substance approximately (1) 540 nm (2) 400 nm (3) 310 nm (4) 220 nm

What This Question Tests

This question requires calculating the maximum wavelength (threshold wavelength) of light that can cause photoelectric emission, given the work function, using the energy-wavelength relationship.

Concepts Tested

Work functionThreshold wavelengthEnergy of a photon

Formulas Used

E = hc/λ

φ = hc/λ_max

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